Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/224

 Volumes; and yet not so much as one of the infinite admirable conclusions that those his writings contain, hath ever been observed, or understood by any one, before Our Friend made them out.

You make me lose the desire I had to understand more in our disputes in hand, onely that I may hear some of those demonstrations which you speak of; therefore either give them me presently, or at least promise me upon your word, to appoint a particular conference concerning them, at which Simplicius also may be present, if he shall have a mind to hear the passions and accidents of the primary effect in Nature.

I shall undoubtedly be much pleased therewith, though indeed, as to what concerneth Natural Philosophy, I do not think that it is necessary to descend unto minute particularities, a general knowledg of the definition of motion, and of the distinction of natural and violent, even and accelerate, and the like, sufficing: For if this were not sufficient, I do not think that Aristotle would have omitted to have taught us what ever more was necessary.

It may be so. But let us not lose more time about this, which I promise to spend half a day apart in, for your satisfaction; nay, now I remember, I did promise you once before to satisfie you herein. Returning therefore to our begun calculation of the time, wherein the grave cadent body would pass from the concave of the Moon to the centre of the earth, that we may not proceed arbitrarily and at randonrandom [sic], but with a Logical method, we will first attempt to ascertain our selves by experiments often repeated, in how long time a ball v. g. of Iron descendeth to the Earth from an altitude of an hundred yards.

Let us therefore take a ball of such a determinate weight, and let it be the same wherewith we intend to make the computation of the time of descent from the Moon.

This is not material, for that a ball of one, of ten, of an hundred, of a thousand pounds, will all measure the same hundred yards in the same time.

But this I cannot believe, nor much less doth Aristotle think so, who writeth, that the velocities of descending grave bodies, are in the same proportion to one another, as their gravities.

If you will admit this for true, you must believe also, that two balls of the same matter, being let fall in the same moment, one of an hundred pounds, and another of one, from an altitude of an hundred yards, the great one arriveth at the ground, before the other is descended but one yard onely: Now bring your fancy, if you can, to imagine, that you see the great